Eyeliner. Dare I say it's a necessary evil for most, if not all, women? It's the one in your makeup bag that can make the most drastic difference, but also be the hardest to master. Too thick or too thin, too dark or too light, sometimes getting it just right is a science in itself.

And before you even apply it, you have to know what you're working with. There are so many different formulas to choose from, it's important to know beforehand what they're all about and what looks you can create with each.

PENCIL:

It doesn't matter if it's a self-sharpening pencil or one that requires more manual labor, when it comes to applying it, this one is probably the most fool-proof. If the pencil is always sharp (which it should be) you can easily control the thickness of the line. It's a great candidate for creating a smoky look, as most formulas can be blended with a brush, sponge, cotton swab or even your fingertip.

Laura Mercier Longwear Creme Eye Pencil

LIQUID:

Liquid liner can be the trickiest of the bunch, but once mastered, it provides a look that's unmatched. It offers a dark, nearly wet line that can really make eyes pop, and it's ideal for creating winged and cateye looks. If you're new in the liquid liner department, try creating small dots along the lash line first, then connect them.

Urban Decay 24/7 Liquid Waterproof

GEL:

If there's a happy medium between pencil and liquid, gel is it. It's creamy texture makes it easy to apply with a small angled brush. It's doesn't have the shine that liquid liner does, which is great if you're after a smokey, more blended look. Also, it offers mega staying power.

Got Pops Gel Liner